NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
| Interpretations | Date |
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ID: aiam4981OpenMr. Brad Beach 389 Terrace Avenue Suite 204 Virginia Beach, VA 23451; Mr. Brad Beach 389 Terrace Avenue Suite 204 Virginia Beach VA 23451; "Dear Mr. Beach: This responds to your letter to Mr. Taylor Vinson o my staff, inquiring about Federal safety standards that apply to objects designed to be attached to the rear and side windows of passenger automobiles. Although you did not specify what this object is, you described the object as being 'not transparent,' rectangular in shape, with dimensions of 12 inches in width by 18 inches in length. The following discussion explains how our safety standards apply to your product. Some general background information on the Federal motor vehicle safety laws and regulations may be helpful. Our agency, the National Highway Traffic Safety Administration (NHTSA), is authorized under the National Traffic and Motor Vehicle Safety Act (Safety Act), to issue safety standards applicable to new motor vehicles and items of motor vehicle equipment. NHTSA, however, does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. Instead, the Safety Act establishes a 'self- certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. The agency periodically tests vehicles and equipment items for compliance with the standards, and also investigates alleged safety-related defects. The agency has issued two Federal Motor Vehicle Safety Standards that might affect your product. These are Standards No. 205, Glazing Materials, and No. 111, Rearview Mirrors. Standard No. 205 specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (70 percent in areas requisite for driving visibility, which includes all windows in passenger automobiles). Standard No. 111 sets performance requirements for rearview mirrors. The standard provides that each inside rearview mirror must provide a specified field of view to the rear of the vehicle. Manufacturers must certify that their new vehicles complies with the applicable requirements of Standards No. 205 and 111. If, before the vehicle were first purchased by a consumer, a subsequent manufacturer or dealer were to install a device that was not readily removable over the glazing and that impaired the field of view to the rear of the vehicle, that subsequent manufacturer or dealer would be required to certify that the vehicle continues to comply with the requirements of Standards No. 111 and 205 with this additional device installed. After a vehicle is first sold to a consumer, modifications to a vehicle are affected by section 108(a)(2)(A) of the Safety Act. That section prohibits manufacturers, distributors, dealers, and repair shops from knowingly 'rendering inoperative' any device or element of design installed on a vehicle in compliance with our standards. Thus, none of these commercial entities may legally install a sun screen device or other device on a vehicle, if the device would cause the vehicle to no longer comply with the requirements of Standards No. 111 and/or 205. In addition, any manufacturer of motor vehicle equipment, such as a device that is mounted on the glazing of motor vehicles and that is not readily removable, is responsible for the recall and remedy of all such devices, if it is determined that the device contains a defect related to motor vehicle safety. You should note that the 'render inoperative' prohibition in section 108(a)(2)(A) of the Safety Act does not affect vehicle owners, who may themselves alter their own vehicles as they please, without violating any provision of Federal law. Thus, Federal law would not prohibit you, as an individual vehicle owner, from installing any devices you wish in the windows of your own vehicle, even if such installation causes the vehicle to no longer comply with Standards No. 205, No. 111, or any other of our safety standards. The agency, however, urges vehicle owners not to take actions that would degrade the performance of the safety features designed into their vehicles. However, you should also note that the individual States have the authority to regulate the operation and use of vehicles by their owners and modifications owners can make to their own vehicles. Each of the States have exercised this authority to establish requirements for vehicles to be registered and operated within their borders. I cannot advise you about the laws established by each of the States. If you wish to learn whether Virginia or any other State prohibits the installation of your device in a vehicle, you may wish to contact the Department of Transportation for those States in which you are interested. I hope this information is helpful. Please feel free to contact Dorothy Nakama of my staff at this address or by telephone at (202) 366-2992 if you have any further questions or need additional information. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam3194OpenMr. Richard Tearle, Product Planing (sic) and Development, Volvo of America Corporation, Rockleigh, NJ 07647; Mr. Richard Tearle Product Planing (sic) and Development Volvo of America Corporation Rockleigh NJ 07647; Dear Mr. Tearle: This is in response to your recent letter and visit to the NHTS regarding the proper designated seating capacity for the Volvo 262C Coupe. The rear bench seat in this vehicle is 53.15 inches wide and has two depressed areas with contoured upholstery to fashion bucket seats. You ask whether the seat may be designated as having only two seating positions.; It is the agency's opinion that the rear seat in the Volvo 262C Coup must have three designated seating positions. The definition of 'designated seating position' provides, in part, that any bench or split-bench seat having greater than 50 inches of hip room shall have not less than three designated seating positions, 'unless the seat design or vehicle design is such that the center position cannot be used for seating' (49 CFR 571.3). The rear seat in the Volvo Coupe is substantially over this 50-inch caveat in the definition, since it has more than 53 inches of hip room. Further, the seat design is not such that the center position cannot be used for seating. The center position is well padded on both the seat cushion and the seat back and there is no impediment to use of the position. This was demonstrated when several persons sat at the center position when your demonstration vehicle was brought to the agency.; Your letter mentions that the Volvo Coupe has less head room than othe Volvo models, yet there is sufficient head room even at the center position for large persons to occupy the seat. Therefore, we do not believe that the vehicle design is such that the center position cannot be used. The fact that the two outboard positions of the rear seat are aesthetically designed to appear as bucket seats is irrelevant, since the center position is a well-padded integral part of the entire bench seat. Other current models have the same type bucket seat appearance in the rear seat, yet because of hip room have three designated seating positions. You might examine the 1978 Oldsmobile Regency Sedan, for example.; We noted in the demonstration model that the rear seat of the Volv Coupe has an arm rest at the center position that folds into the seat back. If the design of this arm rest were modified to be permanently attached to the seat cushion, the center position could not be used., The bench seat would then qualify as a two-person seat under the definition of 'designated seating position'.; Finally, I would emphasize that this letter only represents th agency's opinion based on the information supplied in your letter and an examination of the demonstration model brought to the agency. The NHTSA does not pass approval on any vehicle design, for any safety standards, prior to the actual events that underlie certification. It is up to the manufacturer to determine whether its vehicles comply with all applicable safety standards and regulations, and to certify the vehicles in accordance with that determination.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4651OpenMr. Douglas Shoner S.E.M. Co. 12244 Truro Avenue Hawthorne, CA 90250; Mr. Douglas Shoner S.E.M. Co. 12244 Truro Avenue Hawthorne CA 90250; "Dear Mr. Shoner: This responds to your letter asking about NHTSA' regulation of foam-filled tires. Specifically, you asked what criteria must be satisfied in order for a foam-filled tire to be approved by this Department, and whether any foam-filled tires have satisfied these criteria. As explained below, NHTSA does not 'approve' any motor vehicle or item of motor vehicle equipment. Instead, the manufacturer itself must certify that the vehicle or item of equipment complies with any and all applicable safety standards. By way of background information, the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq., the Safety Act) gives this agency the authority to issue safety standards applicable to new motor vehicles and new items of motor vehicle equipment. When the agency has issued an applicable safety standard, section 108(a)(1)(A) of the Safety Act (15 U.S.C. 1397(a)(1)(A)) provides that no person shall 'manufacture for sale, sell, offer for sale, or introduce or deliver for introduction in interstate commerce, or import into the United States' any new motor vehicle or new item of equipment unless the vehicles or equipment comply with the applicable standard. A manufacturer is not required to get 'approval' or 'recognition' from this agency before selling its motor vehicles or items of motor vehicle equipment. In fact, NHTSA has no authority under the Safety Act to approve, certify, or otherwise endorse any commercial product. Instead, section 114 of the Safety Act (15 U.S.C. 1403) establishes a self-certification process under which every manufacturer is required to certify that each of its products meet all applicable Federal safety standards. I note that, following a telephone conversation with you, Marvin Shaw of my staff sent you a copy of our September 2, 1986 letter to Mr. Andrew Kroll explaining how NHTSA's regulations apply to foam-filled tires. That letter remains an accurate expression of this agency's regulation of foam-filled tires. If you have any further questions or need additional information on this subject, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Stephen P. Wood Acting Chief Counsel Enclosure"; |
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ID: aiam1453OpenMr. Erik Sundelin, Tire Department, Trellaborgs Gummifabriks Aktiebolag, S-23101 Trelleborg-Sweden; Mr. Erik Sundelin Tire Department Trellaborgs Gummifabriks Aktiebolag S-23101 Trelleborg-Sweden; Dear Mr. Sundelin: This responds to your February 20, 1974 request for a determination o whether two of your motorcycle treadwear indicator designs conform to the S6.4 requirements of Standard 119 *New pneumatic tires for vehicles other than passenger cars.*; The treadwear indicator requirements have been amended by deleting al of the portio of S6.4 that begins 'The indicators shall, as a minimum'. this means that the manufacturer determines for himself the location and design of the six treadwear indicators requires (three in the case of motorcycle tires). He must assure himself that when the indicator is reached, the tread at that point o the tire is worn to a depth of on-sixteenth of an inch (or one-thirty-second of an inch in the case of motorcycle tires).; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4201OpenMr. David M. Wise, Gary Precision Products, 530 Old Post Road No. 3, Greenwich, CT 06830; Mr. David M. Wise Gary Precision Products 530 Old Post Road No. 3 Greenwich CT 06830; Dear Mr. Wise: This is in reply to your letter of August 7, 1986, asking if Federa Motor Vehicle Safety Standard No. 108, or any other Federal regulation applies to a plastic ice scraper with a reflector on it that you may manufacture.; Although the title of Standard No. 108 is *Lamps, Reflective Devices and Associated Equipment*, the reflective devices covered by the standard are those that are mounted on the rear and side of a motor vehicle, which are necessary for signalling and the safe operation of vehicles during darkness and other times of reduced visibility. It does not apply to ice scrapers. Nor does the other Federal motor vehicle safety standard dealing with reflectivity, Standard No. 125 'Warning Devices,' or any other regulation of this Department.; I hope this answers your question. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1003OpenMr. R. O. Sornson, Manager, Environmental & Safety Relations, Chrysler Corporation, Detroit, MI 48231; Mr. R. O. Sornson Manager Environmental & Safety Relations Chrysler Corporation Detroit MI 48231; Dear Mr. Sornson: In response to your letter of November 15, 1972, requestin interpretations of the amendments to Standard No. 108 published on October 7, 1972 (37 FR 21328), I enclose an order of the Administrator responsive to your request.; A correction will be published in the near future reinstating th designation 'S5.1' and changing the designation of paragraph S5.3, adopted on January 4, 1973, to 'S5.2'.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam3897OpenMr. Hiroshi Shimizu, Assistant Manager, Overseas Operations Dept., Tokai Rika Co., Ltd., Oguchi-Cho, Aichi Pref., 480-01, Japan; Mr. Hiroshi Shimizu Assistant Manager Overseas Operations Dept. Tokai Rika Co. Ltd. Oguchi-Cho Aichi Pref. 480-01 Japan; Dear Mr. Shimizu: This responds to your letter of December 19, 1984, concerning th requirements of Federal Motor Vehicle Safety Standard No. 209, *Seat Belt Assemblies*. You noted that section S4.1(e) of the standard provides that 'A Type 1 or Type 2 seat belt assembly shall be provided with a buckle or *buckles* readily accessible to the occupant....' [Emphasis added.] You asked whether the standard would permit a seat belt assembly with two buckles as shown in the schematic attached to your letter. The answer is that while Standard No. 209 would permit such an assembly, whether such an assembly can be installed in a particular vehicle is determined by Standard No. 208, *Occupant Crash Protection*.; Standard No. 208 specifies performance requirements for the protectio of occupants in a crash. Section S4.1.2.3.1 provides that Type 2 lap and shoulder belt systems used in passenger cars must have a nondetachable shoulder belt. Likewise, S4.2.2 provides that certain trucks and buses with Type 2 belts must have a nondetachable shoulder belt. The belt system you illustrated in your diagram consists of one continuous loop of webbing which serves as both the lap and shoulder belt. However, your design provides a separate buckle for the shoulder anchorage and thus an occupant could release the shoulder buckle and use the belt solely as a lap belt. Thus, we would not consider your design to have a nondetachable shoulder belt.; In addition, section S7.2 of the standard sets requirements for th latch mechanism of non-automatic seat belt assemblies used in passenger cars and certain trucks and buses. Section S7.2(c) requires that the latch mechanism of non-automatic seat belt assemblies used in passenger cars and certain trucks and buses. Section S7.2(c) requires that the latch mechanism used in those vehicles must release at a single point. Therefore, a two buckle system could not be used in those vehicles.; I hope this answers your question. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5040OpenMr. Timber Dick Safeline Children's Products Co. 5335 W. 48th, Suite 300 Denver, CO 80212; Mr. Timber Dick Safeline Children's Products Co. 5335 W. 48th Suite 300 Denver CO 80212; "Dear Mr. Dick: This responds to your letter concerning Standard No 213, 'Child Restraint Systems,' and the Sit'n'Stroll child restraint system you manufacture. The restraint is designed to be rear-facing for children weighing up to 25 pounds. Your letter relates to our April 22, 1992 interpretation to Mr. Mark Sedlack regarding rear-facing restraints for children weighing up to 25 pounds. In that letter, I stated that under Standard No. 213, such a restraint could be tested with either the six-month-old or the three-year-old dummy in the agency's compliance tests. I further stated that the restraint must physically permit the dummies to be positioned in accordance with the procedures in S6.1.2.3.1 of Standard No. 213. If the restraint cannot permit the dummies to be so positioned, the restraint cannot be recommended for children weighing more than 20 pounds. You ask whether we would consider the Sit'n'Stroll as permitting the proper positioning of the three-year-old dummy. The photographs enclosed with your letter show the dummy in the restraint with its legs at a right angle to the torso. The backs of the dummy's heels rest on the standard seat assembly's seat back, about five inches below the top of the seat back. At the outset, I must note that NHTSA cannot provide you with an unqualified answer on whether your restraint accommodates the three-year-old dummy, because we do not know the details of your design. However, we can offer general guidance on the positioning of the dummy's legs, an aspect of the dummy's positioning that is of particular concern to you. S6.1.2.3.1(b) and (d) of Standard No. 213 specify the procedure for positioning the three-year-old dummy's legs in the child restraint. S6.1.2.3.1(b) states: '... Extend the legs of the dummy as far as possible in the forward horizontal direction, with the dummy feet perpendicular to the centerline of the lower legs.' S6.1.2.3.1(d) states: '... R otate each dummy limb downwards in the plane parallel to the dummy's midsagittal plane until the limb contacts a surface of the child restraint system or the standard seat .... Position the limbs, if necessary, so that limb placement does not inhibit torso or head movement in the standard's dynamic tests....' Based on the photographs you enclosed, the Sit'n'Stroll permits the dummy's legs to be positioned as specified in S6.1.2.3.1(b). That is, the legs are extended 'as far as possible' in the forward horizontal direction. The standard does not specify whether 'forward' is relative to the standard seat assembly or to the child. However, interpreting 'forward' as relative to the seat assembly would have the effect of disallowing the use of the three-year- old dummy to test a rear-facing restraint, since the positioning procedures would be inappropriate for the restraint. In the absence of language in the standard to that effect, we are disinclined to so conclude. Instead, we conclude 'forward' as used in S6.1.2.3.1(b) is relative to the child. Although the Sit'n'Stroll permits the legs to be positioned in accordance with S6.1.2.3.1(b), under S6.1.2.3.1(d) the leg placement must not inhibit torso or head movement during the dynamic tests of the standard. It does not appear that the dummy's legs would inhibit torso or head movement due to the forward (relative to the seat assembly) movement of the torso and head in the dynamic tests. However, we cannot make a definite determination based on the information in your letter. Please note that it is likely that NHTSA will propose amending Standard No. 213 such that a child restraint designed for use with children weighing up to 25 pounds would be tested with a new array of child test dummies, such as the 9- month-old dummy described in subpart J of our regulations (49 CFR Part 572). It is possible that a future amendment to the standard could specify that a new dummy, such as the 9-month-old, will be used instead of the 3-year-old dummy to test such a child restraint. NHTSA has announced its intention to consider rulemaking on incorporating new dummies, including the 9-month-old, in Standard No. 213 compliance tests. This intention was discussed at length in NHTSA's 'Planning Document on Potential Standard 213 Upgrade,' July 1991. I also would like to note our concern with the ability of your restraint to meet Standard No. 213's occupant excursion requirement (S5.1.3.2). S5.1.3.2 states: 'In the case of each rear-facing child restraint system, in a dynamic test ... no portion of the target point on either side of the dummy's head shall pass through the transverse orthogonal planes whose intersection contains, the forward-most and top-most points on the child restraint system surfaces ....' It appears from your photograph that the restraint's seat back might be too low to enable the restraint to meet S5.1.3.2 in a dynamic test. One means of avoiding any potential compliance problem with the excursion requirement would be for your company to raise the height of the seat back on this child restraint system. I hope this information is helpful. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam2785OpenMr. Donald L. Fowler, Ullman, Fowler & Jeffries, Inc., 2231 Devine Street, Columbia, SC 29205; Mr. Donald L. Fowler Ullman Fowler & Jeffries Inc. 2231 Devine Street Columbia SC 29205; Dear Mr. Fowler: This responds to your March 6, 1978, letter asking about the complianc responsibilities of a final-stage manufacturer who mounts a body on a motor vehicle chassis. In the situation you describe, the chassis would have been tested for compliance with the standards by the chassis manufacturer and the body would have been tested by the body manufacturer. You ask whether the final assembler would be required to crash test the vehicle as assembled.; The chassis manufacturer has responsibilities for compliance wit Federal safety standards that are outlined in Part 567, *Certification*, and Part 568, *Motor Vehicles Manufactured In Two Or More Stages*, of our regulations. The chassis manufacturer must include with its chassis an incomplete vehicle document that describes how to complete the vehicle without impairing the compliance of the chassis with Federal safety standards. Although not required by our regulations, body manufacturers often provide documents addressing the compliance of their vehicle bodies with applicable safety standards. If a body that complies with Federal standards is mounted in accordance with the instructions of the incomplete vehicle document, the final-stage manufacturer can ordinarily assume that the completed vehicle complies with the safety standards. Based upon this assumption, it can certify that the vehicle complies with all applicable standards.; By following the instructions of the incomplete vehicle manufacture and relying upon the statements of the body manufacturer, the final-stage manufacturer would be considered to have exercised due care in ensuring that the vehicle complies. However, if the final-stage manufacturer does not follow the incomplete vehicle manufacturer's instructions or in some way makes a major modification that would affect the compliance of the vehicle, it might become necessary for it to undertake some further testing to ensure continued compliance. The amount of further testing, in these instances, would depend upon the extent of modification of the vehicle body or chassis.; For your information, our safety standards and regulations are locate in Volume 49 of the Code of Federal Regulations Parts 501 *et seq*. I am enclosing a sheet which details the applicability of Federal standards to various vehicles.; If after reading this letter, you still have questions that require meeting, contact Roger Tilton of my staff.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0242OpenMr. L.C. Lundstrom, Director, Automotive Safety Engineering, General Motors Technical Center, Warren, Michigan 48090; Mr. L.C. Lundstrom Director Automotive Safety Engineering General Motors Technical Center Warren Michigan 48090; Dear Mr. Lundstrom: This is in reply to your letter of May 7, 1970, requesting approval o an equivalent test procedure for interior compartment doors, in place of those specified in S3.3.1(a) and (c) of Standard No. 201.; Since the phrase 'approved equivalent test procedure' appeared in th initial Federal motor vehicle safety standards, the Bureau's position on this subject has undergone some clarification. The manufacturer's primary responsibility is to produce vehicles or equipment that, when tested according to the applicable standards, meet the stated requirements. Although a manufacturer is responsible for ensuring that his products meet all the requirements of the standards, there is nothing in the Act that requires a manufacturer to perform any predetermined series of test. If a particular test is actually 'equivalent' to the procedure described in the standard, in the sense that the test results can be accurately correlated to the standard's requirements, there is no need to requires approval of the Bureau, and there would be no legal significance to the approval if given. Conversely, if the test is not equivalent, so that an item that 'passed' the test might still fail to conform to the standard, the request would be actually for a lowering of the standard, which could not be done without rulemaking procedures. For this reason, we will not grant the approval in the form in which it was requested.; The procedure that you describe does, however, appear to be a distinc improvement in the method of testing this aspect of performance. We intend to initiate rulemaking procedures directed at amending the standard to incorporate that test.; Sincerely, Rodolfo A. Diaz, Acting Associate Director, Motor Vehicl Programs; |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.